| Biography | |
|---|---|
 Dr. Andrei Ivanets National Academy of Sciences of Belarus, Belarus |
|
| Title: Calcium magnesium zirconium phosphate: From adsorption to radioactive wastes disposal | |
| Abstract: An important part of the work of nuclear power plants and other nuclear industry enterprises is the processing of liquid radioactive waste (LRW), in particular, their minimization and transfer to a compact form acceptable for further disposal. In this regard, the development of new efficient technologies for processing LRW and the improvement of existing ones does not lose its relevance. Since LRW is an aqueous solution of complex radionuclide and chemical composition, the most promising approach is to use selective inorganic adsorption and ion exchange materials. Currently various materials are being studied that are more or less indifferent to the salt background and are suitable for the processing of LRW: oxides and hydroxides of metals, modified natural adsorbents, titanosilicates, ferrocyanides of transition metals, phosphates of multivalent metals, including those obtained from industrial and agricultural wastes. The adsorption strength of radionuclides is one of the factors that must be taken into account when evaluating the possibility of practical use of adsorbents. This is due to the risks associated with the possibility of migration of radionuclides to the external environment at various technological stages of handling spent adsorbents. As a rule, spent adsorbents are immobilized in cement or other matrices. A number of technological operations are carried out, which may include centrifugation and removal of excess liquid phase, grinding, physical and chemical processing, etc. At each stage, compliance with regulated requirements for the safe handling of liquid and solid radioactive waste (SRW) is required. Sodium zirconium phosphates NaZr2P3O12 and calcium zirconium CaZr4P6O24, also known as NZP materials, due to the features of the crystal chemical structure, the NZP phosphate family has a number of unique properties, in particular, the stability of the structure with respect to ion substitution in various lattice sites, high thermal and radiation resistance, which makes them a promising material for the immobilization of long-lived radionuclides for subsequent safe disposal. In this paper, we attempted to synthesize adsorbents based on calcium magnesium phosphates using mixed tertiary and hydrogen calcium magnesium phosphates obtained by phosphating natural dolomite under various conditions, and zirconyl nitrate as a zirconium-containing precursor. As far as we know, there are no data in the literature on the synthesis of NZP phosphate materials using the proposed method. The relevance of the synthesis of these phosphates is due, on the one hand, to their supposed high efficiency as adsorbents of long-lived radionuclides of cesium, strontium and cobalt, and, on the other, to the possibility of immobilization and safe disposal of spent adsorbents by heat treatment and transformation into calcium zirconium CaZr4P6O24 and magnesium zirconium MgZr4P6O24 phosphate ceramic matrices. The main highlights of report are included: i. The facile synthesis of calcium magnesium zirconium phosphate adsorbents was developed; ii. The obtained adsorbents had superior adsorption affinity towards 137Cs, 85Sr, 60Co radionuclides; iii. The formation of MZr4P6O24 (M: Ca, Mg) ceramic matrix during adsorbents calcination was shown; iv. Insights into phosphate adsorbents development for radionuclides immobilization was demonstrated. The presented results are important for understanding the possibilities of efficient liquid radioactive wastes decontamination by calcium magnesium zirconium phosphate adsorbents and safe disposal of spent adsorbents in ceramic matrix. | |
| Biography: Dr. Andrei Ivanets is the General Scientific Secretary of the National Academy of Sciences of Belarus and is a Scientific Supervisor of the Laboratory of Adsorbents and Adsorption Processes at the Institute of General and Inorganic Chemistry NAS Belarus (IGIC NAS Belarus). Scientific works on colloidal chemistry and the study of inorganic porous materials with a given structural-phase organization and surface chemistry. He developed the inorganic membranes, adsorbents and heterogeneous catalysts for the processes of water treatment from toxic metal ions, radionuclides, dyes and pharmaceutical substances. He has published over 100 manuscripts on environmental chemical engineering. Dr. Ivanets is member of the Presidium of the National Academy of Sciences of Belarus, member of the Council on defense of candidate and doctoral theses at IGIC NAS Belarus, Chairman of editorial-publishing Board of NAS Belarus. Since 2013, he has been Chairman of the Council of Young Scientists of the National Academy of Sciences of Belarus. Currently, Dr. Ivanets dedicates much of his time developing advanced inorganic materials for liquid radioactive waste decontamination and radionuclides immobilization. He and his team as well focus on the Advanced Oxidation Processes and sustainable water technologies. | |
